Question : Have you considered flying out of an airport besides Terrance B. Lettsome International Airport (EIS)?
Answer : Departing from Terrance B. Lettsome International Airport is not the only way to get to San Francisco International Airport. Try looking for flights from Cyril E. King Airport (STT) as well. Over the upcoming months, flights from STT to SFO are being priced 53% cheaper than flights from EIS to SFO. Being only 29 miles away, it's easily accessible for most.
Question : How long do most people stay in San Francisco?
Answer : Of course you're not most people, but if you were, you'd stay roughly one week.
Question : Can you cut down on flight costs by changing the day of the week you travel to San Francisco?
Answer : In March, Wednesday is your cheapest day to fly. Being flexible with your travel days garners even more savings during booking.